“It was a major earthquake in scale and magnitude, the strongest in the past 100 years,” said President Enrique Pena Nieto in an address from the National Disaster Prevention Center’s headquarters, where he was supervising the emergency response.

The US Geological Survey put the magnitude slightly lower, at 8.1. That is the same as a devastating 1985 earthquake that killed more than 10,000 people in Mexico City — the country’s most destructive ever.

In the capital, people ran out of buildings — many in their pajamas — after hearing warning sirens go off just before midnight (0500 GMT Friday).